The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An internal combustion engine is a complex mechanism involving a great number of mechanical, moving parts subject to high speeds, high temperatures, forces of large magnitude, fatigue, friction, contamination, and corrosion. Lubrication through the circulation and application of oil within the engine is well known in the art as a means to reduce wear by friction, reduce heat, and remove contaminants from particular surfaces. Under normal engine operation, internal combustion engines of various configurations and fuel types utilize an oil pump to circulate and distribute oil from an oil collection area or an oil pan through an oil channeling system to critical areas, such as engine bearings, cylinders, and head valve mechanisms. However, the oil pump does not operate when the engine is turned off.
Gravity acts upon oil in an engine. Oil which was distributed during the last operating cycle is slowly pulled by gravity through the engine into the oil pan, leaving engine surfaces exposed and insufficiently lubricated. While engine start-up activates the oil pump, and oil begins to circulate through the engine again, engine start-up involves a period of time in which the components of the engine operate with little or no oil present. Under ideal conditions, this oil-starved period is short, and the engine operates at idle conditions, reducing the wear on the engine. However, under non-ideal conditions, significant damage to the engine can result. One example of non-ideal conditions includes cold environmental conditions. Oil increases internal frictional forces or viscosity in cold temperatures and becomes thickened. Oil containing contaminants can also become thickened. Thickened oil takes longer for the oil pump to move through the oil channeling system, increasing the period in which damage is done to the engine. Another example of non-ideal conditions includes start-ups followed by immediate operator demand for engine output. If an operator starts and engine and immediately applies pedal input to move the vehicle, the increased forces applied within the engine as a result of the pedal input in the absence of proper lubrication can drastically increase wear upon engine components. Another example of non-ideal conditions includes dealer staging operations, in which unsold vehicles are moved around a dealer's lot with great frequency, sometimes involving a multitude of brief engine starts wherein the vehicle only moved slightly, but each start-up can include operation without proper lubrication. Any of these non-ideal conditions can increase wear upon the engine components and cause maintenance issues.
Methods are known to pre-lubricate an engine by injecting oil onto critical engine parts before operation. Methods are known whereby an electric oil pump, frequently an auxiliary oil pump to the main oil pump, is activated to distribute oil prior to engine start-up. One method to initiate pre-lubrication is to activate the electric oil pump on a timer or upon a control signal of some programmed frequency. This method is effective to pre-lubricate the engine, however the periodic activation of the electric oil pump can create a significant drain upon the battery of the vehicle, creating or exacerbating parasitic drain issues. Additionally, the actual protection created by timed pre-lubrication can be dependent upon how recently the last injection occurred before the start-up event. Another method to initiate pre-lubrication is to accept a keyed ignition request from an operator but delay actual engine start-up briefly while the electric oil pump is activated. This method is effective in pre-lubricating the engine, but the delay imposed upon the operator may be a source of dissatisfaction with the operator. Another method to initiate pre-lubrication includes activating the electric oil pump upon a signal from a keyless entry system, typically by a key fob radio frequency device. This method can be effective but is dependent upon the time elapsed between the keyless entry command and the engine ignition, and additionally is ineffective where the operator has not locked the vehicle, such as in a garage.